1. Technical Field
This invention relates to containers such as blow molded plastic jugs which are widely used in the dairy industry and others for the expendible packaging of dairy products and other liquids and tamper indicating caps for engagement thereon.
2. Description of the Prior Art
Prior neck finishes on containers of this type may be seen in U.S. Pat. Nos. 2,162,711 of June, 1939; 2,162,712 of June, 1939; 3,650,248 of March, 1972; 3,980,195 of September, 1976; 4,354,609 of October, 1982; 4,402,415 of September, 1983, 4,418,828 of December, 1984; 4,497,765 of February, 1985, 4,534,480 of August, 1985; and 4,561,553 of December, 1985.
In each of the above U.S. Patents there are individual neck spiral thread configurations which require a cap with a matching single spiral thread configuration for engagement thereon and have the common fault of requiring selective testing rotation of the cap on the threaded neck of the container before the single thread patterns engage.
Additionally, partial semi-annular thread patterns comprising ribs are disclosed in U.S. Pat. Nos. 4,589,461 of May, 1986 and 4,666,053 of May, 1987.
In the '561 patent, several short angular ribs are circumferentially spaced on the inner surface of the depending annular wall of a cap and in the '053 patent a pair of vertically spaced short annularly disposed ribs are disclosed on the neck finish of the container.
Additional segmented semi-annular thread patterns are disclosed in U.S. Pat. Nos. 3,885,696, 4,298,129 and 5,213,224.
In U.S. Patent '696, a closure for a container with a lid is disclosed in which a series of separate partial multiple thread patterns are formed on a neck finish. Each of the threads extend only a partial way on the neck finish arc limited to an effective two vertical threads.
In U.S. Patent '129, a child-proof snap on twist off safety cap and container is disclosed in which an annular barrier flange is positioned on the bottom edge of the cap which requires a quarter turn twist to disengage for removal of the cap.
In U.S. Patent '224, a snap on screw off cap and container neck is disclosed having non-vertical fastening configuration ratchet teeth and a number of lead-in thread configurations.
The present invention provides an improved novel neck finish for a container such as a blow molded plastic jug on which a multiple spiral thread pattern configuration of continuous spiral threads are engaged in vertical and circumferentially spaced relation to one another with a thin wall plastic cap that may be pushed onto the container, snapping over three threads of the multiple spiral thread pattern, the cap having a top and a depending annular wall with multiple annular spiral thread patterns circumferentially and vertically spaced formed on the inner surface of said depending wall of the improved cap. The combination of the improved cap and improved neck finish of the container results in a rapid and positive engagement of three of the multiple continuous thread patterns on the respective neck finish with those on the inner surface of the depending wall of the cap requiring a final partial turn of the cap after sealing the closure.